The leaves or pods of the senna plant (Cassia senna) have been used by Arab physicians for their laxative properties since at least the ninth Century. Today, senna is a U.S. Food and Drug Administration (FDA)-approved nonprescription drug and an ingredient in several commercial laxatives.

There are over 400 known species of Cassia. Both the leaves and the seedpods (fruit) have laxative activity, due to the presence of compounds called anthraquinones. These compounds found in senna are also found in other plants with laxative properties, including cascara (Cascara sagrada), rhubarb (Rheum spp.), and aloe (Aloe vera). Senna accelerates defecation, in contrast to softening the stools, as some laxatives do. When taken at much higher than recommended doses or when used for the long term (laxative abuse), adverse effects, such as low blood potassium, may occur.

Some evidence supports the use of senna in adults for the treatment of chronic constipation or constipation induced by childbirth or drugs. In children, the available evidence suggests that mineral oil and lactulose may be safer and more effective than senna for treating chronic constipation. Some experts believe that senna is a more acceptable laxative than cascara or aloe for drug-induced constipation. Approximately 80% of terminal cancer patients who are taking opioids for pain relief require laxatives. Some evidence suggests that senna may be as effective and safe as lactulose for these patients.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

The available evidence suggests that mineral oil and lactulose may be safer and more effective laxatives than senna for treating children with chronic constipation. Further research is required before conclusions may be made.

C

Although senna is commonly used to reduce constipation, the available clinical research is mixed. Some studies have shown that senna may be more effective than some other laxatives and have fewer side effects. Further trials are needed before a conclusion may be made.

C

Some evidence supports the use of senna as an adjunct therapy in the treatment of cancer patients who have constipation as a result of taking opioids for pain. Further research should assess the length of time such patients may safely use senna.

C

Senna has been examined as a potential treatment for postoperative constipation. Additional research is needed before a conclusion may be made.

C

Senna has been examined as a method for preparing the bowel before diagnostic procedures that require clear visualization of the abdominal area. Further studies are needed in this area.

C

Data on the use of senna for cleaning the colon in preparation for colonoscopy are mixed. Some adverse effects have been reported with this use. Additional research is needed before a conclusion can be made.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Doses must be determined for each patient, due to individual variability. A tea may be made from dried senna leaves or fruits.

For chronic constipation, 1-2 tablets (or one teaspoon) of Senokot® have been taken daily by mouth. One to two tablets of Senokot-S®, increasing to a maximum of three tablets twice daily, or reducing to one tablet daily or every other day, have been taken by mouth in a nursing home setting. A dose of 14.8 grams of Agiolax® (senna combined with a bulk laxative) has been taken by mouth daily in geriatric patients. Four tablets daily of Senokot®, given in divided doses in the morning and evening until a bowel movement occurs, or a maximum of 16 doses, have been taken by mouth for postpartum constipation. One teaspoon of senna granules, consisting of 450 milligrams of Cassia acutifolia pod, has been taken by mouth once daily after childbirth, followed by either one-half or one whole teaspoon of senna granules at bedtime. One teaspoon of water-soluble senna extract, standardized to 20 milligrams of sennosides, has been added to one cup of water and taken by mouth daily for at least six weeks. Glysennid® has been taken by mouth in an initial dose of one tablet nightly, increased (to a maximum of three tablets daily) or decreased (to a minimum of one tablet daily) according to individual response. Senna leaves or pods have been taken by mouth in doses of 0.6-2 grams daily, together with a dose of 20-30 milligrams of sennoside B.

For constipation (opioid-induced), half of a Senokot® concentrated senna tablet has been taken by mouth to counteract each 60 milligrams of codeine or its equivalent. Senna (starting with 0.4 milliliters daily) has been taken by mouth for 27 days.

For constipation (postoperative), 1-2 tablets (one teaspoon) of senna (Senokot®) has been taken by mouth as a single dose.

For a laxative or bowel preparation for procedures, senna (one package diluted in a glass of water) has been taken by mouth the evening before surgery. Two tablets of Senokot® DX (14 milligrams of sennosides A and B) have been taken by mouth on the two evenings before X-ray examination. A dose of one milliliter per kilogram of body weight (to a maximum of 75 milliliters) of a syrup containing 2.0 milligrams of sennoside A and B per milliliter (X-prep®) has been taken by mouth. A dose of one milliliter per kilogram of body weight of Prunasine® (to a maximum dose of 75 milliliters) has been taken by mouth. A dose of 180 milligrams of senna has been taken by mouth one day prior to colonoscopy. A dose of 75 milliliters of a senna laxative has also been taken by mouth the day before colonoscopy. Twenty-four tablets of 12 milligrams senna have been divided into two doses and taken by mouth.

Children (under 18 years old)

There is no proven safe or effective dose for senna in children.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid with known allergy or hypersensitivity to senna, its constituents, or members of the Fabaceae family. Occupational exposure to senna may cause allergy in the absence of increased risk of asthma.

Side Effects and Warnings

Senna is likely safe for short-term use for constipation, including by the elderly, women after childbirth, and cancer patients taking narcotic drugs. The adverse effects of senna reported in clinical trials are mostly gastrointestinal in nature. Experts have suggested that the benefits of senna during pregnancy be weighed against possible adverse effects.

Although the effect has not been well studied in humans, senna may decrease the absorption of some herbs and supplements, due to the presence of anthranoid compounds.

Senna may increase the risk of bleeding. Caution is advised in patients with bleeding disorders or those taking drugs, herbs, or supplements that may increase the risk of bleeding. Dosing adjustments may be necessary.

Use cautiously in patients who have had an obstruction of the gastrointestinal tract.

Use cautiously in patients with hemorrhoids, stomach ulcers, or inflammatory bowel condition, as senna may cause these conditions to worsen.

Use cautiously in patients taking diuretics or other laxatives, as senna may further reduce levels of blood potassium.

Use cautiously in patients taking digoxin, as senna may increase side effects of digoxin.

Use cautiously in patients with a history of gallstones, as senna may quicken passage through the gastrointestinal tract, which may increase the risk of gallstones.

Use cautiously in children less than 12 years of age.

Avoid long-term use of senna (e.g., more than 7-10 days), due to the potential for side effects, including potentially dangerous changes in heart rhythm. Long-term use of laxatives may lead to "lazy-bowel syndrome," in which the stomach and intestines gradually lose the ability to contract without being stimulated by the laxative.

Avoid in patients with known allergy or hypersensitivity to senna, its constituents, or members of the Fabaceae family.

Pregnancy and Breastfeeding

Use of senna by pregnant or breastfeeding women remains controversial. The American Academy of Pediatrics has classified senna as "usually compatible with breastfeeding." The World Health Organization regards its use while breastfeeding as safe for the infant. However, senna use is contraindicated in Britain and Germany. Clinical trials have reported that senna is safe and effective for women experiencing postpartum-induced constipation, with a lack of adverse effects on breastfed babies. One study reported that senna does not appear to be secreted in breast milk. Experts have suggested that the benefits of senna during pregnancy be weighed against possible adverse effects.

Constipation is a common complaint during pregnancy. The use of fiber supplements and senna has been supported.

Older senna products may have caused increased frequency of diarrhea in breastfed infants, but studies of modern products found this effect lacking.

Although the effect has not been well studied in humans, senna may decrease the absorption of some drugs, due to the presence of anthranoid compounds.

Senna may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Although the effect has not been well studied in humans, senna may decrease the absorption of some herbs and supplements, due to the presence of anthranoid compounds.

Senna may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.